Re: Fix for seg picksplit function

On Wed, Nov 10, 2010 at 4:53 PM, Alexander Korotkov <aekorotkov(at)gmail(dot)com>wrote:

> Hmm, the second for loop in gseg_picksplit uses "i < maxoff" whereas the
>> other one uses <=. The first is probably correct; if the second is also
>> correct it merits a comment on the discrepancy (To be honest, I'd get
>> rid of the "-1" in computing maxoff and use < in both places, given that
>> offsets are 1-indexed). Also, the second one is using i++ to increment;
>> probably should be OffsetNumberNext just to stay consistent with the
>> rest of the code.
>>
> Actually I can't understand the purpose of FirstOffsetNumber
> and OffsetNumberNext macros. When I wrote the patch I though about sortItems
> as about "clean from all these strange things" array, that's why I didn't
> use OffsetNumberNext there. :)
> I see only way to save logic of these macros is to use array starting from
> FirstOffsetNumber index like in gbt_num_picksplit.
>
For example, if we assume, that OffsetNumberNext can do something other that
just increment, that we shouldn't use it in loop on sortItems, but should do
following things:
1) Do additional loop first to calculate actual items count. (Because we
don't know how OffsetNumberNext increases the index. Probably it can
increase it by various value.)
2) Fill sortItems using separate index.

----
With best regards,
Alexander Korotkov.